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Fertilizer for Healthy Plants

August 31, 2021

Fertilizer for Healthy Plants

Fertilizer for Healthy Plants

All plants require light, air, water, and nutrients to grow. As they mature, plants often use up the naturally occurring nutrients in the soil around the root zone. These nutrients need to be regularly replaced in order for the plants to continue to grow and remain strong, fertilizers can help with this.


There are three numbers listed on all fertilizer packaging.

  • The first number is nitrogen (N) which is responsible for promoting strong leaf and stem growth as well as plant colour. So, when foliage is normally a bright green and suddenly becomes pale, chances are nitrogen is required.
  • The second number is phosphorus (P) which promotes strong root development that is essential for delivering nitrogen and other nutrients to the leaves. It also encourages greater flower production, in the case of fruit, results in a larger crop.
  • The third number is potassium (K) which is needed for general vigor. It strengthens plants to resist insects and disease and to better withstand poor soil and drought.

Together, the three elements are referred to as primary or macronutrients. Micronutrients include copper, iron, manganese, zinc, boron, chlorine, and molybdenum. Some or all of these may be included in the formulation and are listed accordingly. The actual number represents the percentage present of that element. Fertilizer often contains in smaller quantities such secondary nutrients as calcium, magnesium, and sulphur.


Different types of plants require different care.

  • Evergreens are mainly foliage plants and require a lot of nitrogen. The most common formula for this group is found in Parkwood® Evergreen & Tree Food 14-7-14.
  • Annuals are grown for their continuous flowering so higher levels of phosphorus would be beneficial. Parkwood® Flower Plant Food 15-30-15 is excellent for promoting blooms that last longer.
  • To minimize the shock of transplanting, a formula like Parkwood® Transplanter 5-15-5 would immediately strengthen and promote root development.
  • Spring lawns need nitrogen to encourage strong, green growth. Parkwood® Lawn Food 18-0-6 is perfect for this purpose.
  • In the fall as the weather gets cooler, lawns start to go dormant and their need for nitrogen is less. Parkwood® Fall Lawn Food 10-0-14 strengthens roots for winter with a higher concentration of phosphorus and builds up resistance to disease and injury with more potassium.
  • A simple way to feed most outdoor plants is with a general fertilizer like Parkwood® All Purpose Plant Food 20-20-20 or Parkwood® Garden-All 4-12-8, specifically formulated for vegetables.
  • For roses, there is a specific blend ‘Rose Food’ granular 7-11-10 that you can apply.

One of the best ways to determine the health of your soil is with a test kit available at all Sheridan Nurseries Garden Centres.

  • Fertilizer comes in a granular slow-release form or a compressed spike that’s pushed into the soil. It’s also available as a powder or liquid that is diluted with water. 16-16-16 is great for hanging baskets, while 23-10-13 works with evergreens and shrubs.
  • Granulars are spread over the surface of the soil or lawn, at the recommended rate, by hand for smaller areas or with a spreader for larger areas. Generally, it lasts 6-8 weeks.
  • Spikes for trees and shrubs, fruit trees, and evergreens are pushed into the ground at the drip line in spring.
  • For mature specimens, a root feeder mixes water with a fertilizer pellet and distributes the solution through a long shaft pushed into the soil. It can also be used for deep watering during periods of prolonged drought.
  • Liquid and powder fertilizers can be applied over a large area with a hose-end sprayer that attaches to a garden hose or, for small jobs, diluted with water.
  • Spring is the best time to fertilize when outdoor plants start growing again.
  • Be aware of the time period that fertilizers release nutrients so you know when or if you need to re-apply.
  • Most granular fertilizer is slow-release and may be applied once or twice a year for perennial and mixed borders.
  • Lawns are fertilized 2-4 times a year depending on their general condition. Fertilizer spikes are put into the ground once in spring.
  • Anything mixed with water is quickly used by plants and is, therefore, applied more often.
  • Grass needs fall feeding. Stop fertilizing after September 1, and roses by August 1. This allows the natural cycle of dormancy to take place rather than forcing growth that may not have time to harden off before winter.
  • Organic Fertilizer is derived from once living vegetable or animal material that may include kelp, seaweed, fish, bone meal (2-14-0), and blood meal (12-0-0). Even manure and compost can be considered organic fertilizers. Inorganic or synthetic fertilizers are manufactured from a chemical process or mined. The concentration of nutrients is better controlled about natural solutions for the garden.

House plants have their own needs.

  • For flowering houseplants try Parkwood® 15-30-15.
  • African violets perform well with Schultz African Violet Plus 8-14-9 or Parkwood® 15-30-15.
  • Orchids like Schultz Orchid Food 19-31-17. Better-Gro makes two products for orchids; Orchid Better Bloom 11-35-15 and Orchid Plus 20-14-13.
  • Even Cactus and Succulents have their own fertilizer. Schultz Cactus Plus 2-7-7 maintains healthy plants and promotes flowering.
  • Fertilize house plants when they show active signs of growth. They often rest from November to March because light levels are low. At this time, it’s better to feed them once every 4-6 weeks. In all cases, read package instructions carefully and follow dilution rates exactly. If in doubt ask the staff of trained horticulturists at your local Sheridan Nurseries Garden Centre.